People are generally aware of the most common causes of hallucinations, like schizophrenia and a really high fever. But lesser known are the more rare causes; here are six you probably haven't heard about.

Susan Scutti works as a reporter for Medical Daily and contributes on occasion to Newsweek magazine. She also writes novels. Her stories, poems, and reviews have been published in The Christian Science Monitor, New York Quarterly, Philadelphia Review of Books, Sensitive Skin, and other journals and anthologies. She graduated from Yale, later earned a Master's from CUNY. Generally, she prefers dogs to cats.